Sunday, 18 August 2013

New study adds further fuel to debate about link between induced abortion and breast cancer

Is there a link between induced abortion and breast cancer?

Any such link has been hotly denied by official bodies but a new study has
added further fuel to this ongoing controversy.

The Bangladesh
study published in the Journal of Dhaka Medical College on risk
factors for breast cancer, led by Dr Suraiya Jabeen, found a statistically
significant 20.62-fold increased risk among women with abortion histories.

Professor Joel Brind, a professor at Baruch College, City
University of New York who is an expert on the abortion-breast cancer
link, has
observed that women in Bangladesh have very traditional childbearing
patterns that reduce breast cancer risk. He first
explains why abortion might increase the risk of breast cancer:

‘First, it is universally accepted that having a child
decreases a woman’s risk of breast cancer, because the maturation of the cells
in the breast into milk-producing cells renders them less susceptible to
becoming cancerous. Second, pregnancy hugely increases the number of breast
cells vulnerable to cancer. A live birth provides enough time for these “progenitor
cells” to differentiate into more mature, more cancer-resistant cells.
Therefore, abortion leaves a woman’s breasts with more places for cancer to
start than were there before the pregnancy began.’

‘Why such a high relative risk? That’s because almost all
women in Bengladesh get married and start having children before they are 21,
and breast-feed all their children as well. Consequently, breast cancer has
been almost unheard of in Bengladesh, until recently.’

Of 73worldwide studies since 1957 (including
this latest) on the association of induced abortion and subsequent development
of breast cancer: 53 studies show an association, and 15 studies show no
association. See specifics here.

And yet many official bodies continue to deny categorically
any link between abortion and breast cancer.

The Royal College of Obstetricians and Gynaecologists in
their 2011 review ‘The Care of Women requesting induced abortion’ (see full
report and summary)
stated with a heady degree of certainty:

‘5.10 Women should be informed that induced abortion
is not associated with an increase in breast cancer risk.’

Their lengthier summary concludes as follows:

‘WHO has concluded that induced abortion does not
increase breast cancer risk. Similarly, in a recent review of the evidence,
ACOG concluded that ‘The relationship between induced abortion and the
subsequent development of breast cancer has been the subject of a substantial
amount of epidemiologic study. Early studies of the relationship between prior
induced abortion and breast cancer risk were methodologically flawed. More
rigorous recent studies demonstrate no causal relationship between induced
abortion and a subsequent increase in breast cancer risk.’

There is an overview of existing studies on the American
Association of American Prolife Obstetricians and Gynaecologists (see AAPLOG
website). It summarises as follows:

‘The possibility of this association has been
persistently and vigorously attacked and denied by the major medical groups
in the country since l994. The ACOG and the NCI have been particularly
strong in opposing any suggestion that there is an association. In so
doing, they have taken certain liberties with their interpretation of the
scientific literature. AAPLOG feels that these liberties lack basic
fairness and balance in reaching their “no association” conclusion.’

It goes on to discuss why such a link might be biologically
plausible:

‘There are two pregnancy related independent risk factors
for breast cancer established in the medical literature:

The first is the protective effect of an early first full
term pregnancy. The landmark study establishing this protective effect
[MacMahon, et al, (1970) Bull WHO 43:209-221] is widely accepted in the
medical world. Obviously, aborting a first pregnancy eliminates the
protective effect against breast cancer for that woman.

The second independent risk factor for breast cancer is
induced abortion. As of 2004, 41 studies had been published in the
worldwide medical literature (including 16 American studies) reporting
data on the risk of breast cancer among women with a history of induced
abortion. 29 (70%) of these studies report increased risk. Thirteen of the
16 (81%) American studies report increased risk, 8 with statistical
significance (at least 95% probability that the result is not due to
chance) irrespective of age at first full-term pregnancy. The relative
risk increase of the 41 studies combined is 30%. (Note: this means
that among aborted women there would be a 30% increase in breast cancer
cases over what would normally be expected).’

‘Breast cancer rates have been rising in Europe and North
America for several decades and are projected to rise further. There is
evidence suggesting that having an abortion may increase a woman's risk of
breast cancer in later life. A 1997 review that pooled 23 studies found that
the risk increased by 30% but authors of a 2001 review have denied a link.
There are clearly powerful vested interests on both sides of this debate and space
precludes the necessary in-depth review. However, it is undisputed that a full
term pregnancy protects against subsequent breast cancer, and that
significantly preterm deliveries make it more likely. The link is therefore
biologically plausible.

While it may be prudent to acknowledge that “the jury is
out” with regard to a possible link between abortion and risk of subsequent
breast cancer, further research is needed to conclude the debate. In the
meantime, and in the interests of informed consent, every woman considering
abortion should be offered as much information about the possible risks as she
wishes.’

The issue has also been previously covered in the CMF Journal Triple Helix but not since 2003.

This is clearly a debate that will run and run and in which
huge vested interests are involved.

In the meantime women should not be fobbed off with the
unjustified absolutism of the summary sentence from the RCOG, as most presently
are.

Rather they should be made aware that a link between
abortion and breast cancer is biologically plausible but that the evidence is
still hotly disputed by researchers, obstetricians and
gynaecologists.

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Kiwi, Christian and Medical

This blog deals mainly with matters at the interface of Christianity and Medicine. But I do also diverge into other subjects - especially New Zealand, rugby, economics, developing world, politics and topics of general Christian and/or medical interest. The opinions expressed here are mine and may not necessarily reflect the views of my employer or anyone else associated with me.

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I am CEO of Christian Medical Fellowship, a UK-based organisation with 4,500 UK doctors and 1,000 medical students as members. The opinions expressed here however are mine, and may not necessarily reflect the views of CMF or anyone else associated with me.